• Key words: Heterohelicenes, non-planar chiral polyaromatic compounds, high-spin organic radicals, spin-polarized organic materials, organic electronics, spintronics.

• Our current research focus is on redox-active non-planar, twisted aromatic systems in particular redox-active heterohelicenes, curved aromatic diimides and π-conjugated organic diradicals. While planar aromatic diimides are well explored over last decades, a plethora of unique electronic, optical properties can be realized by twisting aromatic diimides into three-dimensional space. Here, we are fascinated to understand the fundamental properties including spin-polarization of these non-planar systems for their potential application in organic electronics, spintronics. We are particularly interested in tweaking 2D-aromatic diimides such as naphthalenediimides (NDI), perylyenediimides (PDI) to create 3D non-planar redox-active chiral polyaromatics such as heterohelicenes, twistacenes and aromatic macrocycles. We utilize rational design approaches to construct the chiral polyaromatics and prepare them using standard organic synthesis methods. A wide range of advanced analytical techniques such as spectroelectrochemical, electron paramagnetic resonance (EPR), nuclear magnetic resonance (NMR), density functional theory (DFT) are implemented for understanding the material properties to a great depth.

• We are also interested in exploring supramolecular chemistry of these helicenes. Using a rational design approach amiphiphilic helicenes (amphihelicenes) are synthesized using standard organic synthesis and self-assembled in appropriate polar/non-polar media. Controlled balance of intermolecular π-π stacking, hydrogen bonding, hydrophobic interactions between amphihelicenes allow us to construct chiral supramolecular nanostructures. A rigour understanding of kinetics of supramolecular process provides control on size, shape and function of the resulting nanostructure. These supramolecular self-assemblies will be studied for applications in CPL emission, electrocatalysis, redox-triggered chiroptical switching, OLEDs and OFETs etc.

• High-spin organic molecules such as organic diradicals for organic spintronics applications is another key interest of the group. π-conjugated organic radicals are open-shell organic molecules with efficient spin-delocalization throughout the conjugated structure and possess unique magnetic, optical and redox characteristics over sterically protected localized organic radicals (eg. nitronyl nitroxide, oxyl) and closed-shell systems. Unlike traditional closed-shell molecules or open-shell organic radicals that typically have singlet (S=0) or doublet (S=1/2) ground state, high-spin organic diradicals possess triplet ground state (S=1) and excited singlet state (S=0).7 Parallel spins (either α or β-spin) with non-zero exchange interaction manifests triplet ground state and fundamental to organic molecule-based ferromagnetism. They potentially exhibit spin-polarization due to ferromagnetic interactions between the spins and in a self-assembled state migration of selective spin (e.g. α-spin) occurs resulting in spin-filtering effect. Few of the examples, crystals of partially oxidized tetrathiafulvalene radical cation (TTF•+) exhibit molecule-based spin-polarization and high conductivity (σRT= 530 Scm-1) promoted by intermolecular π-orbital overlap, low on-site Coulomb repulsion energy. Our interest lies in developing organic diradicals that provide opportunity to achieve combined spin-alignment and selective spin conduction in a single molecular system i.e. co-existence of magnetism and charge transport or simply a conducting magnet.

• Mothika, V.S., Albino, M., Yerramsetti, P. K., Brookfield, A., Collsion, D., Chechik, V., Avestro, A. J. Zimmerman-Möbius fjord aromaticity: Redox-triggered aromaticity switching in electroactive hetero[5]helicene (di)radicals. Manuscript in Communication. 2022.

• *Mothika, V.S., Baumgarten, M., Scherf, U. Neutral, π-radical-conjugated microporous polymer films of nanoscale thickness for potential use in magnetoelectronics and sensor devices. ACS Appl. Nano Mater., 2019, 2, 4832-4841. (Cover Art)

• *Mothika, V.S., Räupke, A., Brinkmann, K. O., Riedl, T., Brunklaus, G., Scherf, U. Nanometer-thick conjugated microporous polymer films for selective and sensitive vapor-phase TNT detection. ACS Appl. Nano Mater., 2018, 1, 6483-6492.

• #Sutar, P., #Mothika, V.S., Jayaramulu, K., Hazra, A., Maji, T. K. Binder driven self-assembly of metal-organic cubes towards functional hydrogels. Nat. Commun., 2018, 9, 1-12.

• Mothika, V.S., Bonakala, S., Atreya, H. S., Balasubramanian, S., Maji, T. K. Amide functionalized microporous organic polymer (AM-MOP) for selective CO2 sorption and catalysis. ACS Appl. Mater. Interfaces., 2014, 6, 4630-4637.

• Mothika, V.S., George, S. J., Maji, T. K. MOF nano-vesicles and toroids: self-assembled porous soft-hybrids for light-harvesting. Adv. Funct. Mater., 2013, 23, 5585-5590. (Cover Art)

• 2020-2022 The Royal Society Newton International fellow, University of York, United Kingdom

• 2019 PBC research fellow, Weizmann Institute of Science, Israel

• 2016-2018 Alexander von Humboldt (AvH) research fellow, Bergische Universität Wuppertal, Germany

• 2020 Member of Royal Society of Chemistry (MRSC), UK

• 2019 The Royal Society Newton International Fellowship

• 2019 PBC Postdoctoral Fellowship, Israel

• 2017 AvH Foundation nomination for 67th Lindau Nobel Laureates Meeting

• 2016 Alexander von Humboldt (AvH) Foundation Research Fellowship

• 2016 Irish Research Council (IRC) Research Fellowship (declined to accept AvH Fellowship)

• 2014 Council of Scientific & Industrial Research (CSIR, India) Travel Grant (Declined to accept DST grant)

• 2010 All India CSIR-NET (JRF), GATE (IIT-Guwahati)

Office

Faculty building 436,
Department of Chemistry
IIT Kanpur,
Kanpur 208016, India

Office Phone: 0512-259-2335

Email: smothika[AT]iitk.ac.in